'Heir' in the Bible

Concerning the Ammonites, thus saith the LORD; Hath Israel no sons? hath he no heir? why then doth their king inherit Gad, and his people dwell in his cities?

Therefore, behold, the days come, saith the LORD, that I will cause an alarm of war to be heard in Rabbah of the Ammonites; and it shall be a desolate heap, and her daughters shall be burned with fire: then shall Israel be heir unto them that were his heirs, saith the LORD.